After the surgical guide was fixed, the implant site preparation continued with a spherical diamond bur (∅4.2 mm) to create a notch in the bone (Figure 12) facilitating the bone approach of the next cylindric diamond bur (Figure 13).

Round diamond bur was used to perform the primary corticotomy.

The outer wall of the sinus was prepared with cylindric diamond burs, in order to prepare the bone slot until it was adapted to the upper and lower support.

The cylindric diamond bur was used to create a cylindric groove in the lateral wall of the maxillary sinus to enable the drilling tools to complete the osteotomy and to provide adequate bone support to the zygomatic implant. The cylindric diamond bur’s tip was placed between the bone and the upper support of the guide, that worked as a fulcrum for the medial movement of the bur against the sinus lateral wall, that was grinded until the bur was seated on the lower support. (Figure 13).

A 4.2 mm diameter drill was positioned between the guide supports and driven inwards up to a mark on the drill (Figure 14), removing the remaining bone under the upper support to allow a free setting of the following centering spoon.

Centering spoon’s site preparation.

The centering spoon (Figure 15) was placed in order to allow the bone site preparation with a 3 mm internal diameter. A centric drilling is always suggested in order to respect the original planning and to avoid a final implant deviation higher than usual. The drilling depth was determined once the drill was stopped by the spoon sleeve (Figure 16).

Main implant site preparation was carried out with a deepness bur and a reduction spoon.

The deepness bur at the end of its path.

The drill No. 1 was used to finalize the bone preparation, taking care to align the bur with the upper and the lower support (Figure 17). The drilling depth was determined by aligning the planned depth mark on the drill with a reference slot on the guide (Figure 18) (The N. 2 and N. 3 final drills are used only in case of D1 bone).

Last bur to finalize the implant site. Note that at this point no other tool, including reduction spoon is needed.

The final drill at the end of the preparation.

A depth probe was inserted into the osteotomy through the guide and the depth of the osteotomy was assessed aligning the planned line on the probe with the mark on the guide (Figure 19).

Depth caliper was used to assess the bone site preparation.

The planned zygomatic implant was screwed into the osteotomy site through the opposite half-sleeve of the guide (Figure 20).

The zygomatic implant was screwed by a dedicated mounter to prevent implant’s deviation.

An implant driver was used to perform the implant’s seating until its final vertical position was aligned with the mark on the guide and the head geometry was helpful to control its final alignment. Moreover, a pin was also used to definitely orientate the prosthetic connection as planned, in order to respect the following correct placement of the selected angulated abutment (Figure 21).

Implant placement was finalized with the aid of a pin to check even if the planned prosthetic connection orientation was achieved.

Finally, the surgical guide was removed simply unscrewing the two fixation screws.

The above-mentioned guided approach allowed the placement of the multi-unit-abutment on the implants before the surgical guide was removed (Figure 22 and Figure 23).

Multi-unit-abutment was screwed on the fixture with the surgical guide still in place.

Implants and abutments in place confirming the surgical plan.